Multi-stage filter cartridge with polyurethane endcaps

Abstract

A filter cartridge is described that is designed to accommodate for example dual stage filtration. The filter cartridge has an endplate structure formed of a heat cured material, such as polyurethane, where at least one of the top end and the bottom end of the outer filter and the inner filter are embedded within the heat cured material. The heat cured material can provide an endplate structure that is convenient for manufacture and that has one or more sealing surfaces to seal with a housing that the filter cartridge is assembled with. For example, the heat cured material of the endplate can seal non-filtered fluid from filtered fluid that has passed through each of the filtration stages available in the cartridge.

1. A filter cartridge comprising:
 an outer filter that includes a first filter media, the outer filter including a central axis; 
 an inner filter that includes a second filter media, the inner filter is arranged within the central axis of the outer filter, such that there is a space between an inner diameter of the outer filter and an outer diameter of the inner filter, the inner filter having an inner diameter with an opening adapted for inserting a standpipe of a filter housing therein; 
 the outer filter and the inner filter having a first endplate structure on a top end of each of the outer filter and the inner filter; 
 the outer filter and the inner filter having a second endplate structure on a bottom end of each of the outer filter and the inner filter, the second endplate structure having an opening in fluid communication with the space between the outer filter and the inner filter and having an opening in fluid communication with the opening of the inner filter; and 
 at least one of the first endplate structure and the second endplate structure is a heat cured material formed onto the outer filter and the inner filter, such that at least one of the top end and the bottom end of the outer filter and the inner filter are embedded within the heat cured material, 
 wherein the second endplate structure includes an inner sealing surface on an inner diameter of the inner filter, and the inner sealing surface includes an overmolded material. 
 
     
     
       2. The filter cartridge of  claim 1 , wherein the heat cured material is polyurethane. 
     
     
       3. The filter cartridge of  claim 1 , wherein the first endplate structure is a single endplate on the top end of the outer filter and the inner filter. 
     
     
       4. The filter cartridge of  claim 1 , wherein second endplate structure is a single endplate on the bottom end of the outer filter and the inner filter. 
     
     
       5. The filter cartridge of  claim 1 , wherein the second endplate structure comprises one endplate on the bottom end of the outer filter and another endplate on the bottom end of the inner filter. 
     
     
       6. The filter cartridge of  claim 1 , the second endplate structure comprising an outer sealing surface on an outer diameter of the outer filter, at least one of the inner and outer sealing surfaces being the heat cured material. 
     
     
       7. The filter cartridge of  claim 1 , wherein the outer filter and the inner filter have substantially the same height from the top end to the bottom end. 
     
     
       8. The filter cartridge of  claim 1 , wherein the bottom end of the inner filter is shorter than the bottom end of the outer filter. 
     
     
       9. The filter cartridge of  claim 1 , wherein the second endplate structure includes a plate portion for receiving the inner filter,
 wherein the inner sealing surface includes a first support portion extending from an inner diameter of the plate portion, a step portion extending from an end of the first support portion away from the plate portion, and a second support portion extending from an end of the step portion away from the first support portion, 
 wherein the overmolded material is disposed on the step portion.